Synthesis of IPN Polymer Hybrids by In-Situ Radical Polymerization Method and Their High Resistivity to Solvent Extraction

Abstract

Abstract Two different types of polymer hybrids having an interpenetrating polymer network (IPN) of the organic gel and silica gel were prepared by the in-situ polymerization method. One type is the IPN polymer hybrids of poly(N,N′-dimethylacrylamide) gel and silica gel that were prepared by simultaneous polymerization of N,N′-dimethylacrylamide and N,N′-methylenebisacrylamide in a methanol solution of tetramethoxysilane (TMOS). The other type is IPN polymer hybrids of polystyrene gel and silica gel that were prepared by the polymerization of styrene monomer in the presence of divinylbenzene and TMOS. Radical polymerization of these organic monomers proceeded effectively in the sol-gel reaction mixture of TMOS, resulting in homogeneous glassy materials. The formation of IPN structure was confirmed by the solvent extraction. The loss of organic elements could be prevented in both cases by the incorporation of cross-linking points in the organic network. The homogeneity of these IPN polymer hybrids were supported by nitrogen porosimetry measurements. The results demonstrated that the porous silicas obtained from the polymer hybrids had high surface areas and large pore volumes and exhibited a sharp distribution of pore size below 2 nm in both types of IPN polymer hybrids. These results indicate a molecular-level integration of the organic gel and silica gel in the IPN polymer hybrids.